Integrated lens-array-on-substrate for optical coupling system and fabrication method thereof

ABSTRACT

An integrated optical coupling device may include a substrate, a coating layer disposed on the substrate, and a prism disposed on the coating layer. The prism may include a first surface and a second surface. The integrated optical coupling device may also include a first lens disposed on the first surface of the prism, a second lens disposed on the second surface of the prism, and an anti-reflection coating layer disposed on the first lens and the second lens.

CROSS-REFERENCE TO RELATED PATENT APPLICATION(S)

The present disclosure is a non-provisional application of, and claimsthe priority benefit of, U.S. Patent Application No. 61/999,317, filedon Jul. 23, 2014, which is herein incorporated by reference in itsentirety.

TECHNICAL FIELD

The present disclosure is related to integrated optical couplingdevices. More particularly, the present disclosure is related tointegrated lens-array-on-substrate for optical coupling and fabricationthereof.

BACKGROUND

The infrastructure of a typical data center is being challenged by theburgeoning growth of cloud computing and mobile internet data usage.Data centers all over the world are transforming the networkarchitectures and fiber network systems to keep place with current needsand future-proof networks to meet higher network capacity. Besides theshift of the network architecture, a major significant transformation isthe upgrade of data speeds across the network. For switch-to-switchconnections, 10 Gb/s connection links are replaced by 40 Gb/s and 100Gb/s systems, based on wavelength division multiplexing (WDM)technologies which utilize four wavelength light for transmissionsignals in parallel. Furthermore, the number of servers and floor spacealso increase to an unprecedented scale. The footprint, cost and powerconsumption of optical modules become a significant factor. Thus,integrated multiplexing/de-multiplexing (Mux/DeMux) components arerequired for module packaging to combine lights of four wavelengths intoone output beam at the transmitter port or to separate four-wavelengthsignals out of a mixed beam at a receiver port.

A conventional coupling lens for Mux/DeMux is illustrated in Error!Reference source not found. 3, formed by adhering two lenses and oneright-angle prism together. The glass lens 1 and glass lens 2 arefabricated by high-temperature molding, and the right-angle prism isfabricated by polishing lens. As such, the fabrication procedures ofthese components are cost ineffective. Error! Reference source notfound. shows the coupling function of an optical coupling device. Theoutput port of the waveguide is fixed at the focus point of glass lens1, which turns the incoming light into parallel light. A parallel lightis then reflected toward glass lens 2, and is focused by glass lens 2 atthe focus point, where a photodiode is placed. The optical systemrequires that all the optical components to be placed exactly in thedesigned optical path; otherwise the coupling efficiency from waveguideto the photodiode is low. The fabrication procedure of a conventionalcoupling lens based on glue-bonding confines the alignment precision, orotherwise the fabrication cost is high.

SUMMARY

The following summary is illustrative only and is not intended to belimiting in any way. That is, the following summary is provided tointroduce concepts, highlights, benefits and advantages of the novel andnon-obvious techniques described herein. Select implementations arefurther described below in the detailed description. Thus, the followingsummary is not intended to identify essential features of the claimedsubject matter, nor is it intended for use in determining the scope ofthe claimed subject matter.

In one aspect, an integrated optical coupling device may include asubstrate, a coating layer disposed on the substrate, and a prismdisposed on the coating layer. The prism may include a first surface anda second surface. The integrated optical coupling device may alsoinclude a first lens disposed on the first surface of the prism, asecond lens disposed on the second surface of the prism, and ananti-reflection coating layer disposed on the first lens and the secondlens.

In one aspect, an imprinting method for forming an integrated opticalcoupling device on wafer level may include: providing a substrate, witha reflection coating disposed thereon; providing an imprinting mold,with void regions shaped according to a designed lens profile; forming amolding material on the substrate; pressing the imprinting mold on themolding material on the substrate; curing the molding material; removingthe imprinting mold; depositing an anti-reflection film on the curedmolding material; and dicing to form an integrated optical couplingdevice.

In one aspect, an integrated optical coupling device may include adouble-polished substrate having a first polished surface and a secondpolished surface opposite the first polished surface, a first coatinglayer disposed on the first polished surface of the substrate, and afirst prism disposed on the first coating layer. The first prism mayinclude a first surface and a second surface. The integrated opticalcoupling device may also include a first lens disposed on the firstsurface of the first prism, a second lens disposed on the second surfaceof the first prism, a first anti-reflection coating layer disposed onthe first lens and the second lens, a second coating layer disposed onthe second polished surface of the substrate, and a second prismdisposed on the second coating layer. The second prism may include afirst surface and a second surface. The integrated optical couplingdevice may further include a third lens disposed on the first surface ofthe second prism, a fourth lens disposed on the second surface of thesecond prism, and a second anti-reflection coating layer disposed on thethird lens and the fourth lens.

In one aspect, an imprinting method for forming an integrated opticalcoupling device on wafer level may include: providing a double-polishedsubstrate, the double-polished substrate having a first surface and asecond surface opposite the first surface; forming a partial-transparentpartial-reflecting layer on the first surface of the substrate; formingan anti-reflection layer on the second surface of the substrate;providing a first imprinting mold with voids regions shaped according toa designed lens profile; providing a second imprinting mold with voidregions shaped according to the designed lens profile; forming a firstmolding material on the first polished surface of the substrate with thepartial-transparent partial reflecting layer; pressing the firstimprinting mold on the first molding material on the substrate; curingthe first molding material; removing the first imprint mold; depositinga first anti-reflection film on the cured first molding material;flipping the substrate; forming a second molding material on the secondsurface of the substrate with the anti-reflection layer; pressing thesecond imprinting mold on the second molding material on the substrate;curing the second molding material; removing the second imprinting mold;depositing a second anti-reflection film on the cured second moldingmaterial; and dicing to form an integrated optical coupling device.

In one aspect, an integrated optical Mux/DeMux device may include adouble-polished substrate, an anti-reflection film, a first filter, asecond filter, a third filter, and a fourth filter. The first filter maybe a band-pass multilayer coating film for a first wavelength. Thesecond filter may be a band-pass multilayer coating film for a secondwavelength. The third filter may be a band-pass multilayer coating filmfor a third wavelength. The fourth filter may be a band-pass multilayercoating film for a fourth wavelength. The integrated optical Mux/DeMuxdevice may also include a first lens disposed on the first filter, asecond lens disposed on the second filter, a third lens disposed on thethird filter, and a fourth lens disposed on the fourth filter.

In one aspect, an integrated optical Mux/DeMux device may include afirst substrate layer, a second substrate layer, a third substratelayer, a fourth substrate layer, and an anti-reflection layer disposedon a top surface of the first substrate layer. The first substrate layermay be a double-polished substrate. The second substrate layer may be adouble-polished substrate. The third substrate layer may be adouble-polished substrate. The fourth substrate layer may be adouble-polished substrate. The integrated optical Mux/DeMux device mayalso include a first filter, a second filter, a third filter, a fourthfilter, and a lens array. The first filter may be a band-reflectionmultilayer coating film for a first wavelength, disposed between thefirst substrate layer and the second substrate layer. The second filtermay be a band-reflection multilayer coating film for a secondwavelength, disposed between the second substrate layer and the thirdsubstrate layer. The third filter may be a band-reflection multilayercoating film for a third wavelength, disposed between the thirdsubstrate layer and the fourth substrate layer. The fourth filter may bea band-reflection multilayer coating film for a fourth wavelength,disposed on a bottom surface of the fourth substrate layer. The lensarray may be disposed on the anti-reflection layer.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are included to provide a furtherunderstanding of the present disclosure, and are incorporated in andconstitute a part of this specification. The drawings illustrateembodiments of the present disclosure and, together with thedescription, serve to explain the principles of the present disclosure.The drawings may not necessarily be in scale so as to better presentcertain features of the illustrated subject matter.

FIG. 1 is a diagram of a novel integrated lens-on-substrate opticalcoupling device for waveguide/fiber to photodiode coupling in accordancewith the present disclosure.

FIG. 2 is a flowchart of a fabrication process for an integratedlens-on-substrate optical coupling device with wafer-level imprintingtechnology in accordance with the present disclosure.

FIG. 3 is a schematic diagram of a coupling system utilizing anintegrated lens-on-substrate optical coupling device in accordance withthe present disclosure.

FIG. 4 is a diagram of a novel integrated lens-array-on-substrateoptical coupling device for waveguide/fiber to photodiode coupling inaccordance with the present disclosure.

FIG. 5 is a schematic diagram of a fabrication procedure for alens-array-on-substrate optical coupling device based on wafer-levelimprinting technology in accordance with the present disclosure.

FIG. 6 is a diagram of a novel integrated lens-array-on-substrate devicefor waveguide/fiber to photodiode coupling, with nano-imprintedisolation trenches, in accordance with the present disclosure.

FIG. 7 is a diagram of a novel integrated lens-array-on-substrate devicefor waveguide/fiber to photodiode coupling, with isolation trenchesformed by dry-etching process, in accordance with the presentdisclosure.

FIG. 8 is a diagram of an integrated lens-on-substrate triplexer devicebased on wafer-level imprinting technology in accordance with thepresent disclosure.

FIG. 9 is a flowchart of a fabrication process for an integratedlens-on-substrate triplexer device based on wafer-level imprintingtechnology in accordance with the present disclosure.

FIG. 10 is a diagram of a novel lens-integrated thin film filter forMux/DeMux with input and output light on the opposite sides of thesubstrate in accordance with the present disclosure.

FIG. 11 is a diagram of a novel lens-integrated thin film filter forMux/DeMux with input and output light on the same side of the substratein accordance with the present disclosure.

FIG. 12 is a diagram of a novel lens-integrated thin film filter forMux/DeMux based on wafer-bonding technology and wafer-levelnano-imprinting technology in accordance with the present disclosure.

FIG. 13 is a diagram of a conventional optical coupling device with twoglass lenses adhered to a right-angle glass prism.

FIG. 14 is a diagram for functional description of the conventionaloptical coupling device of FIG. 13.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present disclosure provides an integrated lens-on-substrate devicebased on wafer-level nano-imprinting technology. Advantages ofwafer-level nano-imprinting technology include, but are not limited to,cost effectiveness, high precision, mass production uniformity, and highyield. FIG. 1 illustrates a novel integrated lens-on-substrate opticalcoupling device 100 for waveguide/fiber to photodiode coupling inaccordance with the present disclosure. The substrate of opticalcoupling device 100 may be, for example, a glass substrate. The prismand two lenses on two surfaces of the prism may be made of polymer bynano-imprinting technology.

FIG. 2 illustrates a fabrication process 200 for an integratedlens-on-substrate optical coupling device (e.g., optical coupling device100) with wafer-level imprinting technology in accordance with thepresent disclosure. Fabrication process 200 may be utilized to fabricatethe optical coupling device 100 of FIG. 1. Fabrication process 200 mayinclude a number of operations including, but not limited to, thoseshown in FIG. 2. Although operations 202-212 in FIG. 2 are shown in aparticular order, in various embodiments some of the operations 202-212may be implemented in orders different from that shown in FIG. 2.Moreover, some of the operations 202-212 may be implemented in paralleland not necessarily in series as shown in FIG. 2. For illustrativepurpose, the following description of fabrication process 200 refers tooptical coupling device 100 of FIG. 1.

At 202, a substrate is provided with reflection coating disposed on top,and an imprinting mold is provided with voids regions shaped accordingto a designed lens profile.

At 204, a molding material is formed on or above the substrate, whichmay be a glass substrate.

At 206, the imprinting mold is pressed on the molding material on/abovethe substrate.

At 208, the molding material is cured and removed.

At 210, an anti-reflection film is deposited on or above the curedmaterial.

At 212, the structure thus formed is diced to form an integrated opticalcoupling device, e.g., optical coupling device 100.

FIG. 3 illustrates a coupling system 300 utilizing an integratedlens-on-substrate optical coupling device in accordance with the presentdisclosure. Referring to FIG. 3, the divergent output beam from awaveguide or a fiber is converged to parallel beam by the first lens onthe prism, and it is then reflected by the prism, and the parallel beamis finally converged on the photodiode aperture by the second lens.

FIG. 4 is a diagram of a novel integrated lens-array-on-substrateoptical coupling device 400 based on wafer-level nano-imprintingtechnology for waveguide/fiber to photodiode coupling in accordance withthe present disclosure. With wafer-level imprinting technology, it isachievable to fabricate arrays of any size with any pitch, while thefabrication precision of the lens surface and lens position is veryhigh. FIG. 5 illustrates a fabrication procedure 500 for alens-array-on-substrate optical coupling device (e.g., optical couplingdevice 400) based on wafer-level imprinting technology in accordancewith the present disclosure.

FIG. 6 illustrates a novel integrated lens-array-on-substrate device 600for waveguide/fiber to photodiode coupling, with nano-imprintedisolation trenches, in accordance with the present disclosure. Theintegrated lens-array-on-substrate device 600 may include isolationtrenches between adjacent lenses, which may be formed directly bywafer-level nano-imprinting technology.

FIG. 7 illustrates a novel integrated lens-array-on-substrate device 700for waveguide/fiber to photodiode coupling, with isolation trenchesformed by dry-etching process, in accordance with the presentdisclosure. The integrated lens-array-on-substrate device may includeisolation trenches between adjacent lenses, which may be formed bydry-etching process. With isolation trenches between the lenses, thelenses are separated. Advantageously, as a result, thermal expansioninfluences on device 700 are thus minimized.

FIG. 8 illustrates an integrated lens-on-substrate triplexer device 800based on wafer-level imprinting technology in accordance with thepresent disclosure. The integrated lens-on-substrate triplexer devicemay be configured for optical coupling of three components.

FIG. 9 illustrates a fabrication process 900 for an integratedlens-on-substrate triplexer device (e.g., triplexer device 800) based onwafer-level imprinting technology in accordance with the presentdisclosure. Fabrication process 900 may be utilized to fabricate thetriplexer device 800 of FIG. 8. Fabrication process 900 may include anumber of operations including, but not limited to, those shown in FIG.9. Although operations 902-922 in FIG. 9 are shown in a particularorder, in various embodiments some of the operations 902-922 may beimplemented in orders different from that shown in FIG. 9. Moreover,some of the operations 902-922 may be implemented in parallel and notnecessarily in series as shown in FIG. 9. For illustrative purpose, thefollowing description of fabrication process 900 refers to triplexerdevice 800 of FIG. 8.

At 902, a double-polished substrate, with first partial-transparentpartial-reflecting coating, may be provided or otherwise disposed on afirst surface of a substrate, and an anti-reflection coating may bedisposed on a second surface of the substrate. The substrate may be aglass substrate.

At 904, a first imprinting mold and a second imprinting mold may beprovided, each with voids regions shaped according to a designed lensprofile.

At 906, a first molding material may be formed on or above the firstsurface of the substrate.

At 908, the first imprinting mold is pressed on the first moldingmaterial on/above the substrate.

At 910, the first molding material is cured and removed.

At 912, a first anti-reflection film may be deposited on or above thecured first molding material.

At 914, the substrate is flipped so that the side that was facingdownward is now facing upward.

At 916, a second molding material is formed on or above the secondsurface of the substrate.

At 918, the second imprinting mold is pressed on the second moldingmaterial on/above the substrate.

At 920, the second molding material is cured and removed.

At 922, a second anti-reflection film is deposited on or above the curedsecond molding material.

FIG. 10 illustrates a novel lens-integrated thin film filter 1000 forMux/DeMux with input and output light on the opposite sides of thesubstrate in accordance with the present disclosure. Referring to FIG.10, the input and output ports are designed at opposite sides of thesubstrate. The benefit of lens integration on thin film filters cansignificantly reduce the coupling complexity when packaging variousfunctional components in one optical module. The four filters aredesigned for four different wavelengths with different film thicknesses.Each filter is fabricated through film deposition, lithographypatterning and dry etch process, which are executed four times tofabricate the four filters. The input port may be coated withanti-reflection coating for all wavelengths.

FIG. 11 illustrates a novel lens-integrated thin film filter 1100 forMux/DeMux with input and output light on the same side of the substratein accordance with the present disclosure. Referring to FIG. 11, theinput and output ports are designed at opposite sides of the substrate.

FIG. 12 illustrates a novel lens-integrated thin film filter 1200 forMux/DeMux based on wafer-bonding technology and wafer-levelnano-imprinting technology in accordance with the present disclosure.Referring to FIG. 12, the thin film filter 1200 may be formed bystacking four glass substrates coated with four differentband-reflection filters together, which may be also integrated with lensbased on wafer-level nano-imprinting technology.

Highlight of Select Features

In one aspect, an integrated optical coupling device may include asubstrate, a coating layer disposed on the substrate, and a prismdisposed on the coating layer. The prism may include a first surface anda second surface. The integrated optical coupling device may alsoinclude a first lens disposed on the first surface of the prism, asecond lens disposed on the second surface of the prism, and ananti-reflection coating layer disposed on the first lens and the secondlens.

In some implementations, the substrate may include one of a glasssubstrate, a silicon substrate, a silicon-on-insulator substrate, asilica substrate, a sapphire substrate, a gallium-arsenide substrate, oran indium-phosphide substrate.

In some implementations, the substrate may include a single-polishedsubstrate.

In some implementations, the coating layer may include a reflectioncoating layer.

In some implementations, the reflection coating layer may include ametal film, a dielectric film, a multilayer dielectric film, or acombination of metal films and dielectric films.

In some implementations, a material of the prism, the first lens and thesecond lens may include polymer, polyimide, epoxy, resin, or acombination thereof.

In some implementations, the prism may include a right-angle prismhaving a right-angle disposed directly facing the coating layer.

In some implementations, the right-angle prism may include an equicruralright-angle prism.

In some implementations, the first lens may be disposed on a first sideof the right-angle, and the second lens may be disposed on a second sideof the right-angle.

In some implementations, the first lens may include an aspheric lens.

In some implementations, the second lens may include an aspheric lens.

In some implementations, an optical axis of the first lens and anoptical axis of the second lens may be mirror-symmetrical with respectto a normal line of the coating layer.

In some implementations, the anti-reflection layer may include asingle-layer dielectric film or a multilayer dielectric film.

In one aspect, an imprinting method for forming an integrated opticalcoupling device on wafer level may include: providing a substrate, witha reflection coating disposed thereon; providing an imprinting mold,with void regions shaped according to a designed lens profile; forming amolding material on the substrate; pressing the imprinting mold on themolding material on the substrate; curing the molding material; removingthe imprinting mold; depositing an anti-reflection film on the curedmolding material; and dicing to form an integrated optical couplingdevice.

In some implementations, the substrate may include a glass substrate, asilicon substrate, a silicon-on-insulator substrate, a silica substrate,a sapphire substrate, a gallium-arsenide substrate, or anindium-phosphide substrate.

In some implementations, a material of the imprinting mold may includesilicon, tungsten carbide, silicon carbide, silicon nitride, titaniumcarbide, tungsten-cobalt alloy carbide, sapphire, or a combinationthereof.

In some implementations, a material of the molding material may includepolymer, resin, polyimide, epoxy, or a combination thereof.

In some implementations, the curing of the molding material may includethermal curing or ultraviolet (UV) curing.

In some implementations, the imprinting method may further include anextra patterning and dry etching process that defines isolation trenchesbetween adjacent lenses.

In one aspect, an integrated optical coupling device may include adouble-polished substrate having a first polished surface and a secondpolished surface opposite the first polished surface, a first coatinglayer disposed on the first polished surface of the substrate, and afirst prism disposed on the first coating layer. The first prism mayinclude a first surface and a second surface. The integrated opticalcoupling device may also include a first lens disposed on the firstsurface of the first prism, a second lens disposed on the second surfaceof the first prism, a first anti-reflection coating layer disposed onthe first lens and the second lens, a second coating layer disposed onthe second polished surface of the substrate, and a second prismdisposed on the second coating layer. The second prism may include afirst surface and a second surface. The integrated optical couplingdevice may further include a third lens disposed on the first surface ofthe second prism, a fourth lens disposed on the second surface of thesecond prism, and a second anti-reflection coating layer disposed on thethird lens and the fourth lens.

In some implementations, the double-polished substrate may include aglass substrate, a silicon substrate, a silicon-on-insulator substrate,a silica substrate, a sapphire substrate, a gallium-arsenide substrate,or an indium-phosphide substrate.

In some implementations, the first coating layer may include apartial-transparent partial-reflecting coating layer, and the secondcoating layer may include an anti-reflection coating layer.

In some implementations, the first coating layer may include ananti-reflection coating layer, and the second coating layer may includea partial-transparent partial-reflecting coating layer.

In some implementations, a reflection ratio of the partial-transparentpartial-reflecting coating layer may be 50%.

In some implementations, the first coating layer and the second coatinglayer may include single-layer dielectric films or multilayer dielectricfilms.

In some implementations, a material of the first prism, the secondprism, the first lens, the second lens, the third lens and the fourthlens may include polymer, polyimide, epoxy, resin, or a combinationthereof.

In some implementations, the first prism and the second prism mayinclude right-angle prisms each of which having a right-angle disposeddirectly facing the coating layer.

In some implementations, the right-angle prism may include an equicruralright-angle prism.

In some implementations, the first lens and the second lens may bedisposed on a first side and a second side of the right-angle of thefirst prism, respectively, and the third lens and the fourth lens may bedisposed on a first side and a second side of the right angle of thesecond prism, respectively.

In some implementations, the first lens may include an aspheric lens.

In some implementations, the second lens may include an aspheric lens.

In some implementations, the third lens may include an aspheric lens.

In some implementations, the fourth lens may include an aspheric lens.

In some implementations, an optical axis of the first lens and anoptical axis of the second lens may be mirror-symmetrical with respectto a normal line of the substrate.

In some implementations, an optical axis of the third lens and anoptical axis of the fourth lens may be mirror-symmetrical with respectto a normal line of the substrate.

In some implementations, the first lens and the third lens may share acommon optical axis.

In some implementations, the second lens and the fourth lens may share acommon optical axis.

In some implementations, the first anti-reflection layer and the secondanti-reflection layer may include single-layer dielectric films ormultilayer dielectric films.

In one aspect, an imprinting method for forming an integrated opticalcoupling device on wafer level may include: providing a double-polishedsubstrate, the double-polished substrate having a first surface and asecond surface opposite the first surface; forming a partial-transparentpartial-reflecting layer on the first surface of the substrate; formingan anti-reflection layer on the second surface of the substrate;providing a first imprinting mold with voids regions shaped according toa designed lens profile; providing a second imprinting mold with voidregions shaped according to the designed lens profile; forming a firstmolding material on the first polished surface of the substrate with thepartial-transparent partial reflecting layer; pressing the firstimprinting mold on the first molding material on the substrate; curingthe first molding material; removing the first imprint mold; depositinga first anti-reflection film on the cured first molding material;flipping the substrate; forming a second molding material on the secondsurface of the substrate with the anti-reflection layer; pressing thesecond imprinting mold on the second molding material on the substrate;curing the second molding material; removing the second imprinting mold;depositing a second anti-reflection film on the cured second moldingmaterial; and dicing to form an integrated optical coupling device.

In some implementations, the double-polished substrate may include aglass substrate, a silicon substrate, a silicon-on-insulator substrate,a silica substrate, a sapphire substrate, a gallium-arsenide substrate,or an indium-phosphide substrate.

In some implementations, a material of the first imprinting mold andsecond imprinting mode may include silicon, tungsten carbide, siliconcarbide, silicon nitride, titanium carbide, tungsten-cobalt alloycarbide, sapphire, or a combination thereof.

In some implementations, a material of the first molding material andsecond molding material may include polymer, resin, polyimide, epoxy, ora combination thereof.

In some implementations, the curing of the first molding material mayinclude thermal curing or UV curing.

In some implementations, the curing of the second molding material mayinclude thermal curing or UV curing.

In one aspect, an integrated optical multiplexing/de-multiplexing(Mux/DeMux) device may include a double-polished substrate, ananti-reflection film, a first filter, a second filter, a third filter,and a fourth filter. The first filter may be a band-pass multilayercoating film for a first wavelength. The second filter may be aband-pass multilayer coating film for a second wavelength. The thirdfilter may be a band-pass multilayer coating film for a thirdwavelength. The fourth filter may be a band-pass multilayer coating filmfor a fourth wavelength. The integrated optical Mux/DeMux device mayalso include a first lens disposed on the first filter, a second lensdisposed on the second filter, a third lens disposed on the thirdfilter, and a fourth lens disposed on the fourth filter.

In some implementations, the anti-reflection film may include an inputport configured to receive lights of four wavelengths. The first lens,the second lens, the third lens and the fourth lens may include outputports configured to output a single-wavelength light respectively.

In some implementations, the first lens, the second lens, the third lensand the fourth lens may include input ports configured to receive lightsof four different wavelengths respectively. The anti-reflection film mayinclude an output port configured to output a multiplexedfour-wavelength light.

In some implementations, the double-polished substrate may include aglass substrate, a silicon substrate, a silicon-on-insulator substrate,a silica substrate, a sapphire substrate, a gallium-arsenide substrate,or an indium-phosphide substrate.

In some implementations, the anti-reflection coating, the first lens,the second lens, the third lens and the fourth lens may be on a sameside of the substrate.

In some implementations, the first lens, the second lens, the third lensand the fourth lens may be on a same side of the substrate. Theanti-reflection coating may be on an opposite side of the substrate.

In some implementations, the first lens, the second lens, the third lensand the fourth lens may include aspheric lenses.

In some implementations, an optical axis of the first lens, an opticalaxis of the second lens, an optical axis of the third lens and anoptical axis of the fourth lens may be in a propagation direction oflights of four wavelengths, respectively.

In some implementations, the first lens, the second lens, the third lensand the fourth lens may be each coated with an anti-reflection coating.

In some implementations, a material of the first lens, the second lens,the third lens and the fourth lens may include polymer, polyimide,epoxy, resin, or a combination thereof.

In some implementations, a fabrication method of the first lens, thesecond lens, the third lens and the fourth lens may includenano-imprinting.

In some implementations, an incident angle of a light may be larger thana Brewster angle of a material of the substrate.

In some implementations, at least one of the first lens, the secondlens, the third lens, or the fourth lens may be integrated and disposedon the anti-reflection film.

In one aspect, an integrated optical Mux/DeMux device may include afirst substrate layer, a second substrate layer, a third substratelayer, a fourth substrate layer, and an anti-reflection layer disposedon a top surface of the first substrate layer. The first substrate layermay be a double-polished substrate. The second substrate layer may be adouble-polished substrate. The third substrate layer may be adouble-polished substrate. The fourth substrate layer may be adouble-polished substrate. The integrated optical Mux/DeMux device mayalso include a first filter, a second filter, a third filter, a fourthfilter, and a lens array. The first filter may be a band-reflectionmultilayer coating film for a first wavelength, disposed between thefirst substrate layer and the second substrate layer. The second filtermay be a band-reflection multilayer coating film for a secondwavelength, disposed between the second substrate layer and the thirdsubstrate layer. The third filter may be a band-reflection multilayercoating film for a third wavelength, disposed between the thirdsubstrate layer and the fourth substrate layer. The fourth filter may bea band-reflection multilayer coating film for a fourth wavelength,disposed on a bottom surface of the fourth substrate layer. The lensarray may be disposed on the anti-reflection layer.

In some implementations, each of the first substrate layer, the secondsubstrate layer, the third substrate layer and the four substrate layerrespectively may include a glass substrate, a silicon substrate, asilicon-on-insulator substrate, a silica substrate, a sapphiresubstrate, a gallium-arsenide substrate, or an indium-phosphidesubstrate.

In some implementations, the first substrate layer, the second substratelayer, the third substrate layer and the fourth substrate layer may bebonded together by wafer-bonding.

In some implementations, a material of the lens array may includepolymer, polyimide, epoxy, resin, or a combination thereof.

In some implementations, a fabrication method of the lens array mayinclude nano-imprinting.

In some implementations, the first lens, the second lens, the third lensand the fourth lens may include aspheric lenses.

In some implementations, optical axis of the lens array may be in apropagation direction of lights of four wavelengths, respectively.

Additional Notes

Although some embodiments are disclosed above, they are not intended tolimit the scope of the present disclosure. It will be apparent to thoseskilled in the art that various modifications and variations can be madeto the disclosed embodiments of the present disclosure without departingfrom the scope or spirit of the present disclosure. In view of theforegoing, the scope of the present disclosure shall be defined by thefollowing claims and their equivalents.

What is claimed is:
 1. An integrated opticalmultiplexing/de-multiplexing (Mux/DeMux) device, comprising: adouble-polished substrate; an anti-reflection film; a first filter,which is a band-pass multilayer coating film for a first wavelength; asecond filter, which is a band-pass multilayer coating film for a secondwavelength; a third filter, which is a band-pass multilayer coating filmfor a third wavelength; a fourth filter, which is a band-pass multilayercoating film for a fourth wavelength; a first lens disposed on the firstfilter; a second lens disposed on the second filter; a third lensdisposed on the third filter; and a fourth lens disposed on the fourthfilter.
 2. The apparatus of claim 1, wherein the anti-reflection filmcomprises an input port configured to receive lights of fourwavelengths, and wherein the first lens, the second lens, the third lensand the fourth lens comprises output ports configured to output asingle-wavelength light respectively.
 3. The apparatus of claim 1,wherein the first lens, the second lens, the third lens and the fourthlens comprise input ports configured to receive lights of four differentwavelengths respectively, and wherein the anti-reflection film comprisesan output port configured to output a multiplexed four-wavelength light.4. The apparatus of claim 1, wherein the double-polished substratecomprises a glass substrate, a silicon substrate, a silicon-on-insulatorsubstrate, a silica substrate, a sapphire substrate, a gallium-arsenidesubstrate, or an indium-phosphide substrate.
 5. The apparatus of claim1, wherein the anti-reflection coating, the first lens, the second lens,the third lens and the fourth lens are on a same side of the substrate.6. The apparatus of claim 1, wherein the first lens, the second lens,the third lens and the fourth lens are on a same side of the substrate,and wherein the anti-reflection coating is on an opposite side of thesubstrate.
 7. The apparatus of claim 1, wherein the first lens, thesecond lens, the third lens and the fourth lens comprise asphericlenses.
 8. The apparatus of claim 7, wherein an optical axis of thefirst lens, an optical axis of the second lens, an optical axis of thethird lens and an optical axis of the fourth lens are in a propagationdirection of lights of four wavelengths, respectively.
 9. The apparatusof claim 1, wherein the first lens, the second lens, the third lens andthe fourth lens are each coated with an anti-reflection coating.
 10. Theapparatus of claim 1, wherein a material of the first lens, the secondlens, the third lens and the fourth lens comprises polymer, polyimide,epoxy, resin, or a combination thereof.
 11. The apparatus of claim 1,wherein a fabrication method of the first lens, the second lens, thethird lens and the fourth lens comprises nano-imprinting.
 12. Theapparatus of claim 1, wherein an incident angle of a light is largerthan a Brewster angle of a material of the substrate.
 13. The apparatusof claim 1, wherein at least one of the first lens, the second lens, thethird lens, or the fourth lens is integrated and disposed on theanti-reflection film.
 14. An integrated opticalmultiplexing/de-multiplexing (Mux/DeMux) device, comprising: a firstsubstrate layer, which is a double-polished substrate; a secondsubstrate layer, which is a double-polished substrate; a third substratelayer, which is a double-polished substrate; a fourth substrate layer,which is a double-polished substrate; an anti-reflection layer disposedon a top surface of the first substrate layer; a first filter, which isa band-reflection multilayer coating film for a first wavelength,disposed between the first substrate layer and the second substratelayer; a second filter, which is a band-reflection multilayer coatingfilm for a second wavelength, disposed between the second substratelayer and the third substrate layer; a third filter, which is aband-reflection multilayer coating film for a third wavelength, disposedbetween the third substrate layer and the fourth substrate layer; afourth filter, which is a band-reflection multilayer coating film for afourth wavelength, disposed on a bottom surface of the fourth substratelayer; and a lens array, which is disposed on the anti-reflection layer.15. The apparatus of claim 14, wherein each of the first substratelayer, the second substrate layer, the third substrate layer and thefour substrate layer respectively comprises a glass substrate, a siliconsubstrate, a silicon-on-insulator substrate, a silica substrate, asapphire substrate, a gallium-arsenide substrate, or an indium-phosphidesubstrate.
 16. The apparatus of claim 14, wherein the first substratelayer, the second substrate layer, the third substrate layer and thefourth substrate layer are bonded together by wafer-bonding.
 17. Theapparatus of claim 14, wherein a material of the lens array comprisespolymer, polyimide, epoxy, resin, or a combination thereof.
 18. Theapparatus of claim 14, wherein a fabrication method of the lens arraycomprises nano-imprinting.
 19. The apparatus of claim 14, wherein thefirst lens, the second lens, the third lens and the fourth lens compriseaspheric lenses.
 20. The apparatus of claim 14, wherein optical axes ofthe lens array are in a propagation direction of lights of fourwavelengths, respectively.